Stop firing orientationchange events at pages that are not visible

LayoutTests/screen_orientation/exit-fullscreen-unlock-orientation-expected.txt

Index: LayoutTests/screen_orientation/exit-fullscreen-unlock-orientation-expected.txt
diff --git a/LayoutTests/screen_orientation/exit-fullscreen-unlock-orientation-expected.txt b/LayoutTests/screen_orientation/exit-fullscreen-unlock-orientation-expected.txt
new file mode 100644
index 0000000000000000000000000000000000000000..66431a0c72712ba9099b0eb0c577e32f4be4dba0
--- /dev/null
+++ b/LayoutTests/screen_orientation/exit-fullscreen-unlock-orientation-expected.txt
@@ -0,0 +1,18 @@
+Tests that when the document fully exits fullscreen, the orientation is locked back to its default value.
+
+On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
+
+
+PASS screen.orientation is "portrait-primary"
+PASS screen.lockOrientation('portrait-primary') is true
+PASS orientationChangeEventCount is 0
+PASS orientationChangeEventCount is 0
+PASS screen.orientation is "portrait-primary"
+PASS orientationChangeEventCount is 1
+PASS screen.orientation is "landscape-primary"
+PASS successfullyParsed is true
+
+TEST COMPLETE
+EVENT(webkitfullscreenchange)
+EVENT(webkitfullscreenchange)
+